• 784 can be written using four 4's:
It is a happy number.
The square root of 784 is 28.
784 is nontrivially palindromic in base 3 and base 13.
It is a nude number because it is divisible by every one of its digits.
It is a Duffinian number.
784 is an undulating number in base 13.
It is a plaindrome in base 5 and base 6.
It is a nialpdrome in base 7, base 11, base 12, base 14 and base 16.
It is a zygodrome in base 6 and base 7.
784 is an untouchable number, because it is not equal to the sum of proper divisors of any number.
784 is the 28-th square number.
It is an amenable number.
It is a practical number, because each smaller number is the sum of distinct divisors of 784
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
784 is a wasteful number, since it uses less digits than its factorization.
784 is an odious number, because the sum of its binary digits is odd.
The cubic root of 784 is about 9.2208725841.
Multiplying 784 by its product of digits (224), we get a cube (175616 = 563).
The spelling of 784 in words is "seven hundred eighty-four", and thus it is an aban number.